A meta-analysis led my myself, Karen Castillioni, and Ellen Welti is now out in Global Ecology and Biogeography! This paper examined the effects of micro- and macronutrient fertilization in grasslands on plant biomass, plant nutrient content, and on the abundance of six arthropod trophic groups.
We found the interesting result that micronutrients applied alone had no effects on plant biomass or arthropod abundance. However, when added with macronutrients (such as nitrogen, phosphorus, and potassium), micronutrients amplified the effect of N, P and K in promoting arthropod abundance, a synergy that did not affect plant biomass (Figure 1).
Micronutrients catalyzed the ability of macronutrients to promote arthropod abundance across all arthropod guilds studied (Figure 2).
This paper was a result of a collaboration with Dr. Lara Souza and Dr. Mike Kaspari at OU and Dr. Chelse Prather and Ryan Reihart at the University of Dayton. We highlight a stoichiometric mismatch between limits of plants and arthropods for metal cations whose biogeochemistry, along with N and P, are being actively rearranged in the Anthropocene.
You can read the paper here. https://rmprather.files.wordpress.com/2020/10/prather-et-al.-2020-geb-meta-analysis.pdf